Wave Loads on Offshore Structures

The author discusses how knowledge of wave-induced loads is essential in both the design and operation of offshore structures. In hostile areas like the North Sea, the significant wave height (mean of the highest one third of the waves present in a sea) can be larger than 2 m 60% of the time. The most probable largest wave height in 100 years can be more than 30 m. The mean wave period can be from 15 to 20 s in extreme weather situations, and it is seldom below 4 s. Environmental load due to current and wind are also important, and in some cases the interactive effect between waves and current is significant. Current velocities of 1-2 m s{sup {minus} 1} and extreme wind velocities of 40-45 m s{sup {minus}1} must be used in designing offshore structures in the North Sea.